|International Journal of Membrane Science and Technology (Volume 4 Issue 1)|
|A Study of High Temperature Mixed Ionic-Electronic Conducting (MIEC) Ceramic Membrane Catalytic Reactor with Single-Step Water-Gas-Shift (WGS) Reaction for Hydrogen Production and Separation|
Elango Balu, J.N. Chung, R.Y. Chein, and Y.C. Chen
Published: 30 May 2017
The feasibility of a catalytic reactor made of mixed ionic-electronic conducting (MIEC) ceramic membrane as a significant option to enhance the production of pure H2 from biomass gasification is established. Thin film SrCe0.7Zr0.2Eu0.1O3-δ (SCZE) membranes supported by a NiO-SrCe0.8Zr0.2O3-δ (NiO-SCZ) tubular structure were developed and tested in simulated high-temperature steam gasification conditions. The main advantage of this membrane reactor design is that it acts as a water gas shift (WGS) reactor for more hydrogen production and simultaneously separates H2 brought in by the feed gas stream and that produced in the membrane. The current process avoids the need for a two-stage reactor setup requiring WGS and H2 separation independently. The possibility of sequestering the isolated pure CO2 stream is also a plus to this membrane reactor.
This paper showcases the experimental analysis of a MIEC ceramic membrane reactor, tested at high temperatures typically found in biomass high-temperature steam gasification systems. Syngas produced from high-temperature gasification of biomass is a complex mixture of hydrocarbons and steam. The current experiments conducted using the tubular SCZE membranes exposed to [CO] and [H2O] vapor at 900°C and 1 atm. showed the feasibility of carrying out WGS reaction and separating hydrogen thus produced in a single pass at gasifier exit conditions .The process described in this paper has not been reported previously in the literature. The results show that SCZE membranes can consistently separate the hydrogen produced by maintaining the integrity of the membrane structure at high temperatures. The overall reactor system efficiency was estimated to be close to 40%.
|Mixed ionic-electronic conductor, Dense ceramic membrane, High temperature biomass gasification, Syngas, Hydrogen separation, Water- gas-shift reaction.|